1. Field of the Invention
The present invention relates to an apparatus for cleaning a glass mask which is used for the manufacture of semiconductor devices.
2. Description of the Prior Art
The process of photolithography for semiconductor wafers, usually, a semiconductor wafer and a glass mask are exposed to light in the state where they are in close contact with each other. The glass mask, after being repeatedly used to be brought into close contact with the wafer, is soiled and, accordingly, requires cleaning before being used in the regeneration process. More specifically, since the glass mask is brought into close contact with the wafer, which is coated with a photosensitive resin or the like, the glass mask is soiled easily with fine residues of the photosensitive resin or the like, and accordingly dust in the air also sticks easily to the glass mask. Furthermore, there is a case where alkaline substances ooze out from the glass mask itself and stick to the surfaces of the glass mask.
Conventionally, the cleaning of the glass mask is performed by manual means or by means of various cleaning apparatuses. There is a conventional cleaning apparatus, in which the glass masks are radially disposed in a body of the apparatus in the form of a cylindrical vessel, and this vessel is rotated, while pure water is jetted from the central portion of the vessel. There is another conventional cleaning apparatus, in which a plurality of glass masks to be cleaned are radially disposed in a body of the apparatus, and this body is rotated in the state where the masks are dipped in pure water, whereby the surfaces of the respective glass masks are washed. In these conventional apparatuses, after completion of the washing operation, the vessel is rotated at a high speed so as to swish water off the masks by centrifugal force, whereby cleaned glass masks are obtained.
In the above-mentioned conventional cleaning apparatuses, however, the glass masks are radially disposed in the body of the apparatus and washed only by jetting pure water or by dipping the masks in pure water. Accordingly, soil struck to the mask, that is, fine residues of the photosensitive resin, oils and fats, such as finger marks of an operator, and alkaline substances oozing outfrom the glass mask, are not completely washed away; therefore the glass mask is not thoroughly cleaned. This is a defect involved in conventional cleaning apparatuses.